Diseases of Game BirdsPart 2 - The Hatchery

Before eggs are set

If you take clean eggs and incubate or hatch them in a dirty
environment you will be putting enormous strain on the resultant
chicks from the moment they are hatched.

The age old question about which came first, the chicken of the
egg applies in this situation. Place dirty eggs in a clean hatchery
or clean eggs in a dirty hatchery and you will inevitably end up
with problems.

There are numerous texts about hatchery construction and
management, so this is not the place to go into this in depth.

Fig
1: Bantams are traditionally used in hatching

You should first determine:

1 If you going to incubate eggs artificially
or under bantams or hens? (Fig 1 - Yes some people are still
doing that very successfully).

2 Where you are going to locate your
hatchery.

3 If this be used for any other purpose.

4 Where you are going to source your eggs.
(Home produced or bought-in)

5 Where you will store eggs if
home-produced?

6 If bought-in, will you inspect the laying
flock or are you assured that the eggs supplied will be, above all
else, clean?

7 What your total target production will be.

8 How many hatches you intend to take off.

9 If you will produce more than one species
from the same set-up.

10 If you want to avoid extra work at weekends.

11 If you will be "candling"
your eggs during incubation.

12 If you will be able to
weigh eggs during incubation.

13 How much extra help you will need on hatch day.

14 How you are going to
handle your day-old chicks.

15 If you planning to vaccinate day-old chicks.

16 How you are going to handle hatchery waste.

17 If you have an outlet for surplus production. The list
could go on and on, but it is important to stick to the basics to
begin with.

Incubation time for the four major species
involved

Planning when you start incubation is usually governed by when
you want the chicks to hatch. They won't either wait or hold back
for you if you plan your schedule so that you have major
tasks (such as setting, transfer to the hatcher or taking off
the chicks) that will fall at a weekend.

You should plan you programme according to the following
incubation times.

Red Legged (French) Partridge 23 days

Pheasants
24 days

Grey (English) Partridges
24 days

Mallard
28 days

Disinfection of footwear (Figs 2 and 3)

The best thing to do is to have boots which are only used in the
hatchery. It takes several minutes to properly disinfect a dirty
boot!

Disinfectant foot baths can be
used provided footwear is water proof.
Another option is to use foam filled disinfectant pads. The
disinfectant should be replenished regularly. It is better to use a
foaming product as you get better penetration of the grooves on the
soles and also the foam carries its own protective coat with
it.

The efficiency of disinfectant foot baths is lost when
contaminated with organic material.

Fig 2: Disinfectant pads should create successful
foam

Fig 3: Once contaminated footbaths are
of little use

The egg

In the laying pen it is critical that the hens have good nest
sites that are clean and dry (Fig 4). These do not have to be
sophisticated. Just remember that cleaning an egg after it has been
laid dirty is no substitute for a clean-laid egg.

The first 15 to 20 minutes after an egg is laid is critical to
the future well-being of the developing embryo. The protective
cuticle on the outside of the egg is a remarkably good barrier to
infection once this period has elapsed.
Scrubbing the egg to remove accumulated
dirt is likely to damage the cuticle and allow penetration of the
shell by bacteria.

Having wild bird nests in the egg wash room should never happen
(Fig 5).

This wash-room floor (Fig 6) had at some time been properly
sealed, meaning that keeping it clean was a simple task.
Once the seal is damaged it
simply means that pockets of dirt will accumulate.

Fig 4: Clean eggs can be produced from simple
systems

Fig 5: This duck nest blows a gaping hole in any
pretence of bio-security

Take care with electrical equipment when being used
close to a water supply (Fig 7). You should
certainly NOT put egg washing machines in a
sink. The risk of electrocution will be dramatically increased.

Take great care to ensure that the egg wash temperature is
properly maintained. It should be at about 40°C and should not be
allowed to fall below 30°C. If this happens organisms may be drawn
into the egg. Follow the instructions on the bottle of sanitizer
you use.

This towel (Fig 8) would have done little to improve the hygiene
of the hands that handled the eggs!

Misting of eggs after washing is commonly carried out. Be sure
that they are only misted and not soaked. If too much is used a
droplet of liquid will gather at the bottom of the egg.

Fig 7: Great care must be taken to avoid
electrocution

Egg boxes

There is no excuse for egg boxes to be contaminated. If your
supplier sends you eggs in boxes which are obviously contaminated
with droppings (Fig 9) what hope is there for the eggs themselves
being clean?

Fig 9: Dirty egg boxes can't contain clean
eggs

The egg store

Eggs need to be stored in a space with even, cool temperature
and high humidity. For storage for up to a week 15-18°C is fine, if
eggs are being stored for longer, then the temperature should be
reduced to 12°C. They should not be exposed to direct
sunlight at any time during storage. Windows in the egg store will
lead to hot zones in the store and reduced hatchability.

Handling eggs for setting

Ideally latex or synthetic gloves
should be worn when setting eggs. However, this makes
safe and speedy handling of the eggs difficult. All jewellery
should be removed before handling eggs (Fig 10).

Fig 10: Rings should not be worn when handling
eggs

Pre-warming

Most shoots have three week's hatching in the incubator at any
one time. It is important that you don't "shock" the incubator when
introducing a new week's eggs. This happens when you introduce a
relatively large number of cool eggs to the incubator. The answer
is to pre-warm the eggs in a warm room (23°C to 24°C) for 12 hours
before placing them in the incubator.

Candling

Shining a bright light through the egg shell reveals a host of
information about the viability and fertility of the egg.
The various changes seen during
incubation can ensure that only healthy eggs are transferred to the
hatcher. Cracks in the shell, which would otherwise be invisible,
can also be easily identified by candling. No eggs with cracks in
the shell should be set to incubate as they are not only very
unlikely to incubate successfully, but are much more likely to be
infected, convert into "bangers" and seriously compromise the
viability of the other set eggs.

The crack in this egg (Fig 11) might well have been detected by
candling, reducing the risk of spreading infection through the
incubator.

Fig 11: Candling should have eliminated this
egg

Fumigation

One of the most common, and cost effective, methods of
disinfection is formaldehyde fumigation (Fig 12). It is vital to
remember that formaldehyde vapour is extremely
toxic. You must never re-enter a building or room which
has been fumigated using formaldehyde until the air has been
completely replaced by either natural or forced ventilation. The
only safe way of producing formaldehyde vapour is electrically
heating prills. Mixing formalin with Potassium permanganate
crystals not only could produce an explosive mixture, but also
generates intense heat, thus increasing the risk of fire.

Fig 12: Formaldehyde fumigation must be safe for
the operator

Provided great care is taken eggs can be
successfully fumigated in the incubator. Always seek advice before
doing this yourself. If you get it wrong you will kill the
incubating chicks! Some people fumigate eggs on the day on which
they are set. This means that 1 and 2 week incubated eggs will also
be fumigated.

Eggs are sometimes sprayed in the incubator. Be absolutely
scrupulous in your hygiene when doing this, as a
contaminated spray is a supremely
efficient way of spreading infection around the incubator (Fig
13).

Fig 13: Take care that mists are
clean

The setter

The setter (or hatcher) is only second to the wash room as a
potential "dirty" zone. It is quite common to place an open tray of
formalin solution in the hatcher to try to reduce this risk. Once
again, great care must be taken. There is some suggestion that the
irritant effect of the vapour on the trachea of the hatching chicks
can cause problems. As with so many things relating
to incubation and hatching there is a lot
of art to it, as well as science!

Chicks must be handled with great care when being taken off for
boxing. They are very fragile and limb injuries at this age make
them valueless.

The enormous volumes of hatch
dust produced when taking chicks from the incubator can
present a real health hazard to the operators. They should, at the
very least, wear disposable dust masks when working in this area of
the hatchery.

Chicks can be successfully vaccinated and treated with
probiotics by coarse spraying when they are taken out of the setter
(Fig 15). Be careful not to expose them to direct heat until they
are dry, or you run the risk of chilling them.

Transport

Properly designed chick boxes (Fig
16) must be used if the birds are
to travel any significant distance. If you are
using plastic boxes, be sure that they are properly
disinfected.

A suitable insulating material, such as shredded newspaper,
should be used to ensure the comfort and safety of the birds in
transport.

Fig 14: Hatchling chicks must be handled with
care

Fig 15: Vaccines and probiotics being sprayed onto
chicks

Fig 16: Use chick boxes for
transport

Fig 17: Over-heating in transport is
dangerous

Pay very close attention to ventilation when transporting
chicks. Remember that sunlight falling on vehicle
windows can cause very rapid rise
in temperature inside. Over-heating in transport
(Fig 17) can lead to very high mortality in the first
days of life.

NADIS hopes that you have found the information in the bulletin useful. Now test your knowledge by enrolling and trying the quiz. You will receive an animal health certificate for this subject if you attain the required standard.

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